Even at 400M difficulty and .15 $ per kwh you'd only have to theoretically produce 29GH/w (more if you use a pool) to cover electricity costs, the Jalapano gets around 133GH/w so the 50GH unit probably has 120-130 GH/w efficiency due to more chips and stuff.
So there is no reason for them to stop taking orders as their units will be useful for a while.
like the GPU age. asics will have to start budgeting for electricity costs and up front investment costs.
we're going through a transition phase until total hashrate *must* plateau eventually.
One big difference, which the OP is trying to point out. GPUs weren't on back order for a year and people weren't running the calculations wrong, IE using the current difficulty as their ROI gauge/calculator. I'm hoping ASIC haven't been over bought, but with the number of new start ups and a YEAR worth of undelivered devices, we are looking at a huge unknown. It doesn't look pretty.